142 Mr. J. Croll on Geological Time, and the probable 



astronomy and geology, viz. that geology deals with unlimited 

 time, as astronomy deals with unlimited space. A little consi- 

 deration , however, will show that there is not much analogy be- 

 tween the two cases. 



Astronomy deals with the countless worlds which lie spread 

 out in the boundless infinity of space ; but geology deals with 

 but one world. No doubt both reason and analogy are favour- 

 able to the idea that the age of the material universe, like its 

 magnitude, is immeasurable — although, however, we have no 

 reason to conclude that it is eternal, any more than we have to 

 conclude that it is infinite. But when we compare the age of 

 the material universe with its magnitude, we must not take the 

 age of one of its members (say, our globe) and compare it with 

 the size of the universe. More than this, we must not take the 

 age of all the presently existing systems of worlds and compare 

 their age with the magnitude of the universe ; but we must take 

 the past history of the universe as it stretches back into the infi- 

 nity of bygone time, and compare it with the presently existing 

 universe as it stretches out on all sides into the infinity of space. 

 For worlds precede worlds in time as worlds lie beyond worlds in 

 space. Each world, each individual, each atom is evidently 

 working out a final purpose, according to a plan prearranged 

 and predetermined by the Divine Mind from all eternity. And 

 each world, like each individual, when it serves the end for which 

 it was called into existence, disappears to make room for others. 

 This is the grand conception of the universe which naturally im- 

 presses itself on every thoughtful mind that has not got into 

 confusion about those things called in science the Laws of 

 Nature. 



But the geologist does not pass back from world to world as 

 they stand related to each other in the order of succession in time, 

 as the astronomer passes from world to world as they stand re- 

 lated to each other in the order of coexistence in space. Be- 

 sides, the researches of the geologist are not only confined to 

 one world, but it is only a portion of the history of that one 

 world that can come under his observation. The oldest of 

 existing formations, so far as is yet known, the Laurentian 

 Gneiss, are made up of the waste of previously existing rocks, 

 and these, again, probably of the waste of rocks still prior. Re- 

 garding what succeeds these old Laurentians, geology tells us 

 much ; but regarding what preceded, we know nothing whatever. 

 For anything that geology shows to the contrary, the time which 

 may have elapsed from the solidifying of the earth's crust to the 

 deposition of the Laurentians — an absolute blank — may have 

 been as great as the time that has elapsed since then till the 

 present day. Physical science limits the age of the globe to a 



